Pearls
Pearls Are Formed By Living Animals
 Unlike gemstones produced deep inside the Earth, pearls are created by living
creatures called mollusks. Mollusks commonly have a soft, unsegmented body
and a hard exterior shell, such as a clam or snail has. These animals live
in marine and freshwater habitats as well as on land. The evolutionary history
of this group extends back some 530 million years, with approximately 100,000
species of mollusks alive today.
Any mollusk that produces a shell can produce a pearl. Nevertheless, naturally
occurring pearls are rare, found in perhaps one of every 10,000 animals. The
cultured pearl industry, which has flourished since the early 20th century,
has developed techniques to greatly improve these odds. Indeed, more pearls
are produced now than at any time in human history.
How Pearls Form
Composition
Contrary to popular belief, pearls hardly ever result from the intrusion of
a grain of sand into an oyster's shell. Instead, a pearl forms when an irritant
such as a wayward food particle becomes trapped in the mollusk. The animal
senses the object and coats it with layers of aragonite ("ah-RAG-uh-nite")
and conchiolin ( "KON-kee-uh-lin"). These two materials are the same
substances the animal uses to build its shell.
Structure
In most pearls, the mineral aragonite is arranged in sheets of flat, six-sided
crystals. Between each sheet, the mollusk secretes a very thin layer of the
membrane-forming protein conchiolin. This composite material is called nacre
("NAY-ker") or mother-of-pearl. The crystalline structure of nacre
reflects light in a unique way, giving so-called nacreous pearls their high
luster. In contrast, some pearls are not nacreous and instead have a low-luster,
porcelainlike surface. The needlelike crystals of aragonite in these pearls
are arranged perpendicularly or at an angle to the surface of the pearl.
The Rough Exterior
Because a pearl is the product of a biological process, its surface often
shows minor imperfections. Furthermore, when a mollusk secretes the microscopic
layers that make up a pearl, each layer does not always encircle the entire
pearl. These uneven layers create additional irregularities on the surface.
As a result, it is easy to distinguish a real pearl from an artificial one
by rubbing it gently across your teeth: a real pearl will feel gritty and an
artificial pearl will feel smooth and slippery.
A Perfect Pearl?
Pearls come in a wide variety of sizes and shapes. And although most people
think of pearls as round, the truth is that irregularly shaped pearls are more
common in nature, while perfectly spherical pearls are extremely rare. A pearl's
size and shape depend on the species of mollusk that produced the pearl, how
long it took to form, the size and shape of the nucleus and where the pearl
formed inside the animal. Pearl farmers increase their chances of obtaining
large, round pearls by using large, perfectly spherical nuclei. Even so, there
are no guarantees. A pearl's size and shape reflect such variables as the temperature
and chemistry of the water, as well as the health of the mollusk.
 Not Just Pearly White
Pearls occur naturally in a spectacular array of colors, ranging from white
to gold, purple and black. A pearl's color depends on both the species of mollusk
that produced the pearl and the environment in which the animal lived. In general,
crystals of aragonite are white or colorless. The natural color of a pearl
is mostly due to conchiolin, which contains organic pigments.
A Distinctive Glow
One of the most distinctive features of a nacreous pearl is the way it seems
to glow from within. This property, known as "luster," gives pearls
their unusual beauty. Luster results from the reflection of light rays not
only off the surface of the pearl, but also off the concentric inner layers
of nacre. Because a pearl's surface is round, it acts as a convex mirror, reflecting
light so that it appears to emanate from within the pearl. The multiple layers
of nacre also give rise to the "iridescence" or "orient" of
pearls—a characteristic that resembles the shimmer seen on a soap bubble.
The layers of nacre act like tiny prisms, refracting light so that it appears
as all the colors of the rainbow.
Costume Jewelry
Because pearls are so rare, people have for thousands of years created substitutes
for the real thing. Records indicate that the ancient Romans made imitation
pearls. And Queen Elizabeth I of England, whose passion for pearls is apparent
in every portrait of her, is said to have established an artificial pearl industry
to supply what nature could not. The techniques for manufacturing imitation
pearls have varied over the centuries and today include coating glass beads
with a mixture of varnish and fish scales or flakes of the mineral mica.
Ancient North America
Throughout the ages, humans have been enchanted by pearls and the shells of
the mollusks that produce them. For example, archaeological evidence indicates
that almost 6,000 years ago in the Persian Gulf region, people were sometimes
buried with a pierced pearl resting in the right hand.
As ancient trade routes gradually expanded and societies developed across
Asia and Europe, pearls became important symbols of wealth, status and religious
belief. Some peoples, including the ancient Sumerians, pre-Columbian Americans
and Pacific islanders, placed an even higher value on the larger and more easily
obtained mother-of-pearl shells. Still a source of widespread fascination,
pearls are now admired and worn by more people than ever before.
The Roman and Byzantine Empires
Ancient Middle Eastern cultures were apparently the first to value pearls
and pearl shells. Interest in pearls later spread to the Mediterranean; in
Persia, the gems were said to be worth their weight in gold. By 100 B.C., the
Mediterranean enthusiasm for pearls had become a craze, and pearl-adorned objects
have been found at archaeological sites across the Roman Empire, from Syria
to North Africa and northern France. According to some historians, one of the
reasons Julius Caesar invaded Britain in 55 B.C. was to obtain freshwater pearls.
Jewelry recovered from Roman Empire sites reveals a taste for combining pearls
with emeralds or emerald plasma (chalcedony) and gold. Jewelry fashions at
this time were consistent throughout the far-flung Empire.
A Timeless Appeal
Throughout history, certain cultures have placed little or no value on pearls
and have focused instead on luminescent mother-of-pearl from mollusk shells.
Before the 19th century, Japanese shell divers who found pearls apparently
did not bother to keep them. Polynesian children are said at one time to have
used pearls as marbles. These and other peoples harvested pearl oysters for
their shells, using the mother-of-pearl for decoration. Abalone was also popular
with many groups, including those in the Americas: people ate the flesh of
the mollusks and used pieces of colorful abalone shell as inlay on carved objects
made of wood, ivory and bone.
Images of dragons playing with a pearllike object are very common in Asian
art. Shells such as this one, from the Silver-lipped Pearl Oyster, were probably
carved for the Western export trade.
A Long History of Opulence
In contrast to much of Western Europe, Russia carried on many Byzantine traditions
well into the 18th century—particularly the lavish use of freshwater
pearls. At the same time, Russia was influenced by Western styles, particularly
from the reign of Peter the Great (ruled 1682-1725) through the end of the
Romanov dynasty in 1917. Both the Russian aristocracy and the gentry owned
pearl jewelry and clothing decorated with the gems. Russian noblewomen often
wore large headdresses, or kokoshniki, decorated with pearls, lace and colored
gemstones.
Royal workshops created a wide range of luxurious pearl objects, often adding
pearl embroidery to rich textiles. On many of the pieces, the designers used
pearls to create floral designs and scroll-like patterns, with the pearls serving
as borders.
A New Trend in Europe and America
During the 1700s and early 1800s, the growing middle-class in both Europe
and the United States developed an interest in pearls—and had the money
to buy them. By the mid-1800s, seed pearls had become the pearls of choice.
Jewelers typically worked with seed pearls imported from India and China that
had been strung on silk or, more commonly, white horsehair. The resulting pieces
of jewelry were so delicate that they often resembled lace, and they were considered
a symbol of purity and gentility. Indeed, an 1870 newspaper article stated
that such pearls were "exquisitely beautiful and constitute an appropriate
and elegant present to a young bride."
Pearls in 18th-century Europe
With the introduction of improved techniques for faceting gemstones in the
1600s, precious stones such as diamonds became as popular as pearls or more
so. Pearls continued to be used throughout the 18th century, however, particularly
among the royal families of Europe. Women of the era wore pearl parures—matched
sets of necklaces, bracelets, earrings and brooches. Pearls also adorned religious
objects, in churches and sometimes synagogues. By the early 1800s, the discovery
of new pearl beds in the Pacific, as well as a revival of fishing grounds in
Central America, prompted a renewed interest in pearls.
China 300 Years of Pearls
Pearls became especially popular in China during the Qing, or Manchu, dynasty,
which ruled from 1644 to 1911. The imperial family and wealthy elite used large
numbers of pearls to enhance costumes and furnishings. In theory, the emperor
himself was supposed to use pearls only from freshwater mussels in Manchuria,
northeastern China, the dynasty's homeland. But imperial art of the period
shows so many big round pearls that at least some probably came from marine
pearl oysters in waters off southern China, Vietnam and perhaps the Philippines.
In addition, imitation pearls were used on some objects.
Fashions at the Turn of the 20th Century
During this period of new industrial fortunes, ostentatious wealth and ornate
style, pearls found favor with American society figures and also with royalty
and titled families from Britain to Russia. An all-white effect was sought
in fine jewelry, achieved by masses of pearls or pearls with diamonds. Swags,
garlands, bows, and tassels were favorite motifs in jewelry design.
Pearls in the Modern Era
At the dawn of the 20th century, people in Europe and the United States began
wearing pearls for less formal occasions—a fashion that persists to this
day. Flappers of the 1920s wore long ropes of pearls as they danced the Charleston.
New designs in jewelry, reflecting Art Nouveau styles and the Arts and Crafts
movement, emphasized irregularly shaped freshwater pearls. Imitation pearls
were in vogue on hats and dresses, both in traditional Western and nontraditional
Eastern styles. In addition, Japanese cultured pearls first reached European
and American markets in the 1930s, although the gems did not become popular
until the 1950s.
Hindu and Muslim Traditions
With pearls so abundant in the Persian Gulf and the Gulf of Mannar (located
between India and Sri Lanka), Indian and Middle Eastern cultures have a long
history of using pearls. Indeed, throughout the Muslim and Hindu worlds, both
men and women have traditionally worn these gems. During the 1700s and 1800s,
some of the world's finest collections of pearls, typically from the Black-lipped
Pearl Oyster and Ceylon Pearl Oyster, were owned by rulers in these regions.
Both Islamic and Hindu philosophies celebrate pearls: in Islamic thought, pearls
represent perfection and completeness. For Hindus, the pearl is one of the
planetary gems, associated with the moon and second only to the diamond in
esteem.
Europe's Favorite Gem
Ongoing exploration of the Americas and recently established trade routes
to the East made pearls available as never before in Renaissance Europe beginning
in the 1500s. The new centers of the pearl trade, Lisbon and Seville, overflowed
with pearls from India, the Persian Gulf and the Caribbean. The upper classes
adorned themselves lavishly in these gems, which became the symbol of wealth,
status and taste in an age of splendor. Irregularly shaped, or baroque, pearls
were especially admired. By the late 1600s, however, people began to favor
less extravagant displays of pearls as a result of a changing religious and
political climate, combined with a decline in pearls arriving from the New
World.
A man wore this brooch, adorned with Scottish freshwater pearls, at the shoulder
or chest to secure his brat, a rectangular cloth slung about the body. A compartment
under the rock crystal dome may have held a religious object. The brooch once
belonged at one time to the MacLeans of Loch Buy.
As products of living animals, pearls are unique among gems. In size, shape
and even color, pearls exist in a stunning diversity of forms—far more
than just small, round and white. Depending on the fashions of the era, the
most sought-after pearls may be perfectly spherical, pear-shaped or irregular.
A single large pearl may provide special elegance, or a cluster of seed pearls
may light up a garment or object of art. With their long and lustrous history,
pearls are more popular than ever.
Our Own Great Age of Pearls
With the arrival of cultured pearls on the international market in the 1930s,
pearls became more available and more affordable than ever before. Although
some people initially rejected cultured pearls, a handful of designers, most
notably Gabrielle "Coco" Chanel, embraced them, using the gems in
her elegantly casual designs. By the 1950s, cultured pearls were essential
accessories for well-dressed women in the United States and Europe. Over the
last several decades, designers have been inspired by the broad range of colors
and sizes of cultured pearls to create both sophisticated pearl jewelry and
whimsical pearl-decorated objects. Pearls may be everywhere today, but they
are still as glamorous as ever; images of movie stars, first ladies and supermodels
wearing pearls only heighten the gems' popularity. Indeed, we are living in
a new Great Age of Pearls.
A Final Word About Pearls
Natural or real pearls are made by oysters and other mollusks. Cultured pearls
also are grown by mollusks, but with human intervention; that is, an irritant
introduced into the shells causes a pearl to grow. Imitation pearls are man-made
with glass, plastic, or organic materials.
Because natural pearls are very rare, most pearls used in jewelry are either
cultured or imitation pearls. Cultured pearls, because they are made by oysters
or mollusks, usually are more expensive than imitation pearls. A cultured pearl's
value is largely based on its size, usually stated in millimeters, and the
quality of its nacre coating, which gives it luster.
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